Motor Vehicle Control Device Media-Tight Polymer Overmolding
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Solution Overview
Problem
Existing control devices for motor vehicle components like transmission, engine, and brake systems face challenges in providing absolute protection against corrosive gases and aggressive media due to incomplete sealing, leading to metal corrosion and potential electrical issues, while also being costly to produce.
Innovation Solution
A control unit with a housing cover that is materially connected to a connecting device via gluing, laminating, or soldering, and completely overmolded with a media-tight polymer, forming a hermetically sealed cavity to protect electronic components from oils, gases, and chemicals, using a cost-effective approach by potentially using non-media-tight materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the housing is closed without complete sealing, then production costs are reduced, but corrosive gases can penetrate and cause metal corrosion
Solution Approach 1:
The sealing solution is divided into two segments: a first sealing element (gasket) that provides primary sealing between the housing and cover, and a second sealing element (polymer coating) that provides secondary sealing and corrosion protection. This segmentation allows each sealing element to be optimized for its specific function while maintaining cost-effectiveness.
Solution Approach 2:
A polymer material is introduced as an intermediary substance that is applied to the housing cover and extends into the cavity. This polymer acts as both a sealing element and a protective barrier against corrosive gases, eliminating the need for complete housing sealing while ensuring reliability.
2Reliability
If complete encapsulation with molding compound is used, then protection against corrosive gases is improved, but production complexity and cost increase due to strict process control requirements
Solution Approach 1:
The sealing and protection function is segmented into two independent elements: a gasket for sealing and a polymer coating for protection. This avoids the need for complete encapsulation while achieving the same protective effect with simpler process control.
Solution Approach 2:
The invention extracts the essential protective function from the complex complete encapsulation process. By using a polymer material that is applied to the housing cover and extends into the cavity, the patent achieves corrosion protection without requiring strict process control of molding parameters.
3Reliability
If welding of housing to stainless steel cover is used, then sealing against corrosive gases is improved, but production cost increases and welding gases cause contamination
Solution Approach 1:
The mechanical welding process is replaced with a combination of mechanical sealing (gasket) and chemical sealing (polymer coating). This substitution eliminates the need for welding while achieving equivalent or superior sealing performance without the associated costs and contamination risks.
Solution Approach 2:
A polymer material is introduced as an intermediary that provides both sealing and protective functions. This polymer is applied to the housing cover and extends into the cavity, providing a seal against corrosive gases without requiring welding operations.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively seals the control unit from environmental influences, enhancing the service life and accuracy of the control device by preventing gas and chemical ingress, thus reducing the risk of corrosion and electrical interference, while being more cost-effective than previous methods.
Implementation Method 1
This housing design does not guarantee absolute tightness against diffusion or permeation. Corrosive gases can get to the circuit carrier over time
Implementation Method 2
This housing design does not guarantee absolute tightness against diffusion or permeation. Corrosive gases can get to the circuit carrier over time
Implementation Method 3
the thermal expansion coefficient of the molding material must be precisely matched to that of the overall structure, consisting of the carrier substrate, components, etc. Otherwise, temperature loads can lead to the formation of gaps between the molding compound and the structure
Implementation Method 4
the connection device electrically connects this electronic component to electronic components outside the cavity
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The invention relates to a control device in a motor vehicle, comprising: a housing cover (4) which has a peripheral edge region (8); a flat, electrical connecting device (2, 3) which has integrated conductive tracks, the housing cover (4) being materially bonded to the connecting device (2, 3) in the edge region (8) and forming a cavity (9) with the connecting device (2, 3); at least one electronic component (7) within the cavity (9), the connecting device (2, 3) electrically connecting the at least one electronic component (7) to electronic components outside of the cavity (9), wherein the housing cover (4) is overmolded with a polymer (5) in a media-tight manner beyond the peripheral edge region (8).